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CVE-2024-56640

Estado: ModificadaAlta (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

net/smc: fix LGR and link use-after-free issue

We encountered a LGR/link use-after-free issue, which manifested as the LGR/link refcnt reaching 0 early and entering the clear process, making resource access unsafe.

or

It is caused by repeated release of LGR/link refcnt. One suspect is that smc_conn_free() is called repeatedly because some smc_conn_free() from server listening path are not protected by sock lock.

e.g.

Calls under socklock | smc_listen_work ------------------------------------------------------- lock_sock(sk) | smc_conn_abort smc_conn_free | \- smc_conn_free \- smcr_link_put | \- smcr_link_put (duplicated) release_sock(sk)

Leer descripción completaMostrar menos

So here add sock lock protection in smc_listen_work() path, making it exclusive with other connection operations.

Detalles técnicos trazas, registros y código del informe original
 refcount_t: addition on 0; use-after-free.
 WARNING: CPU: 14 PID: 107447 at lib/refcount.c:25 refcount_warn_saturate+0x9c/0x140
 Workqueue: events smc_lgr_terminate_work [smc]
 Call trace:
  refcount_warn_saturate+0x9c/0x140
  __smc_lgr_terminate.part.45+0x2a8/0x370 [smc]
  smc_lgr_terminate_work+0x28/0x30 [smc]
  process_one_work+0x1b8/0x420
  worker_thread+0x158/0x510
  kthread+0x114/0x118

 refcount_t: underflow; use-after-free.
 WARNING: CPU: 6 PID: 93140 at lib/refcount.c:28 refcount_warn_saturate+0xf0/0x140
 Workqueue: smc_hs_wq smc_listen_work [smc]
 Call trace:
  refcount_warn_saturate+0xf0/0x140
  smcr_link_put+0x1cc/0x1d8 [smc]
  smc_conn_free+0x110/0x1b0 [smc]
  smc_conn_abort+0x50/0x60 [smc]
  smc_listen_find_device+0x75c/0x790 [smc]
  smc_listen_work+0x368/0x8a0 [smc]
  process_one_work+0x1b8/0x420
  worker_thread+0x158/0x510
  kthread+0x114/0x118

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

AV:L/PR:L sin UI indica escalada local; use-after-free permite crash DoS o elevación de privilegios en el kernel SMC del protocolo de red.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix LGR and link use-after-free issue\n\nWe encountered a LGR/link use-after-free issue, which manifested as\nthe LGR/link refcnt reaching 0 early and entering the clear process,\nmaking resource access unsafe.\n\n refcount_t: addition on 0; use-after-free.\n WARNING: CPU: 14 PID: 107447 at lib/refcount.c:25 refcount_warn_saturate+0x9c/0x140\n Workqueue: events smc_lgr_terminate_work [smc]\n Call trace:\n  refcount_warn_saturate+0x9c/0x140\n  __smc_lgr_terminate.part.45+0x2a8/0x370 [smc]\n  smc_lgr_terminate_work+0x28/0x30 [smc]\n  process_one_work+0x1b8/0x420\n  worker_thread+0x158/0x510\n  kthread+0x114/0x118\n\nor\n\n refcount_t: underflow; use-after-free.\n WARNING: CPU: 6 PID: 93140 at lib/refcount.c:28 refcount_warn_saturate+0xf0/0x140\n Workqueue: smc_hs_wq smc_listen_work [smc]\n Call trace:\n  refcount_warn_saturate+0xf0/0x140\n  smcr_link_put+0x1cc/0x1d8 [smc]\n  smc_conn_free+0x110/0x1b0 [smc]\n  smc_conn_abort+0x50/0x60 [smc]\n  smc_listen_find_device+0x75c/0x790 [smc]\n  smc_listen_work+0x368/0x8a0 [smc]\n  process_one_work+0x1b8/0x420\n  worker_thread+0x158/0x510\n  kthread+0x114/0x118\n\nIt is caused by repeated release of LGR/link refcnt. One suspect is that\nsmc_conn_free() is called repeatedly because some smc_conn_free() from\nserver listening path are not protected by sock lock.\n\ne.g.\n\nCalls under socklock        | smc_listen_work\n-------------------------------------------------------\nlock_sock(sk)               | smc_conn_abort\nsmc_conn_free               | \\- smc_conn_free\n\\- smcr_link_put            |    \\- smcr_link_put (duplicated)\nrelease_sock(sk)\n\nSo here add sock lock protection in smc_listen_work() path, making it\nexclusive with other connection operations."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net/smc: inicializar close_work antes para evitar advertencias Encontramos una advertencia que indicaba que close_work se canceló antes de la inicialización. ADVERTENCIA: CPU: 7 PID: 111103 en kernel/workqueue.c:3047 __flush_work+0x19e/0x1b0 Workqueue: eventos smc_lgr_terminate_work [smc] RIP: 0010:__flush_work+0x19e/0x1b0 Rastreo de llamadas: ? __wake_up_common+0x7a/0x190 ? trabajo_ocupado+0x80/0x80 __cancelar_temporizador_trabajo+0xe3/0x160 smc_cerrar_cancelar_trabajo+0x1a/0x70 [smc] smc_cerrar_aborto_activo+0x207/0x360 [smc] __smc_lgr_terminate.part.38+0xc8/0x180 [smc] proceso_uno_trabajo+0x19e/0x340 subproceso_trabajador+0x30/0x370 ? proceso_uno_trabajo+0x340/0x340 kthread+0x117/0x130 ? __kthread_cancel_work+0x50/0x50 ret_from_fork+0x22/0x30 Esto se debe a que cuando se activa smc_close_cancel_work, p. ej., el controlador RDMA es rmmod y se termina el LGR, conn->close_work se vacía antes de la inicialización, lo que genera WARN_ON(!work->func). __smc_lgr_terminate | smc_connect_{rdma|ism} ------------------------------------------------------------- | smc_conn_create | \\- smc_lgr_register_conn para conn en lgr->conns_all | \\- smc_conn_kill | \\- smc_close_active_abort | \\- smc_close_cancel_work | \\- cancel_work_sync | \\- __flush_work | (close_work) | | smc_close_init | \\- INIT_WORK(&close_work) Solucione esto inicializando close_work antes de establecer la conexión."
    }
  ],
  "lastModified": "2026-08-04T11:22:16.417",
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